Chitosan nanoparticles: Polyphosphates cross-linking and protein delivery properties

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Chitosan nanoparticles are commonly prepared using ionotropic gelation with anionic polyphosphates like Tripolyphosphate (TPP).
• Achieving stable size and surface charge in chitosan nanoparticles remains a challenge.
• TPP is a trivalent anion effective for cross-linking chitosan, particularly in drug delivery.

Purpose of the Study:

• To investigate the efficacy of Hexametaphosphate (HMP) as an alternative cross-linking agent to TPP for chitosan nanoparticle preparation.
• To compare the properties of chitosan nanoparticles cross-linked with HMP versus TPP.
• To evaluate the impact of HMP on nanoparticle formation, stability, and drug loading capacity.

Main Methods:

• Chitosan nanoparticles were prepared using ionotropic gelation with both HMP and TPP as cross-linking agents.
• A comparative study was conducted under varying complexation conditions.
• Bovine Serum Albumin (BSA) was used as a model drug to assess drug loading efficiency.

Main Results:

• Chitosan/HMP nanoparticles exhibited higher drug loading efficiency (96.3%) compared to chitosan/TPP nanoparticles (91.87%).
• HMP, a hexavalent molecule, provides more binding sites for interaction with chitosan, potentially leading to stronger ionic complexation.
• While HMP improved drug loading, TPP-cross-linked particles demonstrated superior stability during storage.

Conclusions:

• Hexametaphosphate (HMP) presents a promising alternative to Tripolyphosphate (TPP) for chitosan nanoparticle formulation, particularly for enhancing drug loading.
• The increased binding sites of HMP contribute to improved nanoparticle formation and higher drug encapsulation.
• Further research is needed to optimize HMP-based formulations for comparable storage stability to TPP-based systems.